Exercises: Understand Zero and Identity Matrices

Work through each section in order. Show your work where indicated.

Grade 9·19 problems·~30 min·Common Core Math - HS Number and Quantity·standard·hsn-vm-c-10

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Fluency Practice

Let $A = \begin{bmatrix}3&1\\2&5\end{bmatrix}$ and $I = \begin{bmatrix}1&0\\0&1\end{bmatrix}$ . Which statement is true?

$AI \neq IA$ for this matrix.

$AI = A$ and $IA = A$ .

$AI = A$ but $IA \neq A$ in general.

$AI = I$ (multiplying by $I$ gives $I$ ).